Covid-19-related restrictions on people’s movements and interactions may be linked to a sharp decline in cases of mosquito-borne dengue fever in 2020, offering new insight into how it might be controlled, according to a study.

The study in the Lancet Infectious Diseases journal found nearly 750,000 fewer cases of dengue than were expected occurred globally in 2020, when the coronavirus pandemic began.

The study's results are surprising...